Mechanical behavior of M-Wire and conventional NiTi wire used to manufacture rotary endodontic instruments

• Published in: Dental materials Vol. 29; no. 12; pp. e318 - e324
• Main Authors: Pereira, Erika S.J., Gomes, Renata O., Leroy, Agnès M.F., Singh, Rupinderpal, Peters, Ove A., Bahia, Maria G.A., Buono, Vicente T.L.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2013
• Subjects: Advanced Basic Science; Dentistry; Endodontic instruments; Endodontics - instrumentation; M-Wire; Materials Testing; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nickel; Nickel–titanium; Tensile Strength; Thermomechanical treatment; Titanium; Endodontic instruments; Nickel–titanium; M-Wire; Thermomechanical treatment
• ISSN: 0109-5641; 1879-0097; 1879-0097
• DOI: 10.1016/j.dental.2013.10.004

Comparison of physical and mechanical properties of one conventional and a new NiTi wire, which had received an additional thermomechanical treatment. Specimens of both conventional (NiTi) and the new type of wire, called M-Wire (MW), were subjected to tensile and three-point bending tests, Vickers microhardness measurements, and to rotating-bending fatigue tests at a strain-controlled level of 6%. Fracture surfaces were observed by scanning electron microscopy and the non-deformed microstructures by transmission electron microscopy. The thermomechanical treatment applied to produce the M-Wire apparently increased the tensile strength and Vickers microhardness of the material, but its apparent Young modulus was smaller than that of conventionally treated NiTi. The three-point bending tests showed a higher flexibility for MW which also exhibited a significantly higher number of cycles to failure. M-Wire presented mechanical properties that can render endodontic instruments more flexible and fatigue resistant than those made with conventionally processed NiTi wires.